Future of jazz guitar amplification?

[EastwoodMike]

Pingu, your sketch makes perfect sense. But can't it be inverted 180 degrees? I may be wrong but I believe that what you call waveguides are the more efficient the higher the frequency, so the dispersed/"broadcast" sound is more trebly than the original. What I have no idea of is the optimal density of the waveguide material, i.e. would a skimpy trumpet-shaped plastic deflector work or would it have to be a heavy chunk of precision-turned metal? My experience so far suggests that volumes and shapes matter more than materials in cab design.

this is along the lines of what I was trying to describe earlier - although I pictured in my mind the driver facing forward and the cab/tube still on its existing tilt frame. Front for audience enjoyment and back for the band’s benefit.

[EastwoodMike]

I’d love to learn more about this. I suspect the execution is more involved than the idea, but why did this take so long? Curious which four established names? How close are they and when might these make their debut? Refinement of class D designs has evolved substantially, some might say revolutionized, in the bass amplification arena. (As someone who schlepped an SVT around for a few years, I don’t think that’s too strong a statement). I would think there’s market share to be gained in the electric guitar side of things with the tube preamp/class D power amp approach.

I don’t own any of these yet but what has raised my eyebrow-

Bluguitar Amp1 Mercury
Victory Duchess V4
DV Mark Little GH250 tube
H&K has some as well

then there are a few quilter offerings of note.

some have been out for a few years. They generally use a proprietary ‘ice’ class D section as does Kemper and B&O allegedly. I also hear this section can have a not so soft top frequency section.
Some have cooling fans, one is fan-on full time.
Not all are ‘clean’ but the Victory is apparently Fenderesque in tone profile. Perhaps less scooped but I don’t know that for myself.
The Amp1 is a beast and Marshallesque is basic tone but can be tweaked. It comes in two models- one higher gain and one ‘low’ gain.

Quilter labs I read have some slightly smarter sections to their power stage to try generate analogue speaker impedance coupling to generate a degree of sponginess in response. I hear nothing but good stuff about Q, especially their later stuff.

I don’t have the time or money to buy things just to try- Australia is too far away, too small and too expensive to have shops carry these on shelves to see and test easily.

I can’t wait for the day you have a Clean tube front end mated to a quilter style back end. I’d love to hear more about the DV mark tube versions that are only just out.
eM

[citizenk74]

Acoustic Image has an upward-firing cabinet:



Didn't they have one with a pair of 10" speakers (Ten-two or something like that) that had one down-firing? Googles... The Ten2:

My Acoustic Image Corus Series III has a down-firing 10" speaker and a defeat-able tweeter. And 300 watts. It's a mover!

[BigDaddyLoveHandles]

My Acoustic Image Corus Series III has a down-firing 10" speaker and a defeat-able tweeter. And 300 watts. It's a mover!

So indecisive, Acoustic Image. Fire downwards, fire upwards, what's next? Sideways?

Oh...



Kidding aside, it makes less of a difference if you are amplifying a bass, since lower frequencies are --- it is less directional, or merely perceived by humans as less directional?

[pingu]

Pingu, your sketch makes perfect sense. But can't it be inverted 180 degrees? I may be wrong but I believe that what you call waveguides are the more efficient the higher the frequency, so the dispersed/"broadcast" sound is more trebly than the original. What I have no idea of is the optimal density of the waveguide material, i.e. would a skimpy trumpet-shaped plastic deflector work or would it have to be a heavy chunk of precision-turned metal? My experience so far suggests that volumes and shapes matter more than materials in cab design.

Yes it could work well upside down too ....

one would have to experiment with different shapes / curves of the waveguide

(sorry i i don’t know the answers re -materials , efficiency , density or shape of the waveguide )

I know in principle it can be done
with an even fz response because
of the bose revolve bluetooth
I use at home , which sounds
really great to me

how are you’re lathe skills ?

har , just thinking out loud here ...
I’ve no intention of building one

[pingu]

I don’t own any of these yet but what has raised my eyebrow-

Bluguitar Amp1 Mercury
Victory Duchess V4
DV Mark Little GH250 tube
H&K has some as well

then there are a few quilter offerings of note.

some have been out for a few years. They generally use a proprietary ‘ice’ class D section as does Kemper and B&O allegedly. I also hear this section can have a not so soft top frequency section.
Some have cooling fans, one is fan-on full time.
Not all are ‘clean’ but the Victory is apparently Fenderesque in tone profile. Perhaps less scooped but I don’t know that for myself.
The Amp1 is a beast and Marshallesque is basic tone but can be tweaked. It comes in two models- one higher gain and one ‘low’ gain.

Quilter labs I read have some slightly smarter sections to their power stage to try generate analogue speaker impedance coupling to generate a degree of sponginess in response. I hear nothing but good stuff about Q, especially their later stuff.

I don’t have the time or money to buy things just to try- Australia is too far away, too small and too expensive to have shops carry these on shelves to see and test easily.

I can’t wait for the day you have a Clean tube front end mated to a quilter style back end. I’d love to hear more about the DV mark tube versions that are only just out.
eM

good survey of what’s out there
thanks EM ....

The Victory demo sounds great
(hey all Victory stuff sounds great to me)
4 pre-amp tunes in there
very nice £700 ....

[sgosnell]

FWIW, Zenith came out with an upward firing stereo speaker system with a cone dispersal above it in the early '60s. My father was a Zenith dealer and we stocked some. It was a great sounding system with really excellent stereo dispersal, but it never really caught on.

[citizenk74]

So indecisive, Acoustic Image. Fire downwards, fire upwards, what's next? Sideways?

Oh...



Kidding aside, it makes less of a difference if you are amplifying a bass, since lower frequencies are --- it is less directional, or merely perceived by humans as less directional?

To be clear, there is also a forward-firing 8" speaker, and little folding legs that allow for a frontal up-tilt. It is very much a 3-D experience. Two channels and a range of digital effects. The plan at the moment is to use it to amplify my drum machine, if and when I can find it.

[pingu]

FWIW, Zenith came out with an upward firing stereo speaker system with a cone dispersal above it in the early '60s. My father was a Zenith dealer and we stocked some. It was a great sounding system with really excellent stereo dispersal, but it never really caught on.

found these pictures of the Zenith speakers
Yes that’s what I’m talking about !!
thanks for remembering them for me Sgosnell

apparently white waveguides are plastic
they look very slightly curved (parabolic ?)
in side view
i heard mention that they had 8” drivers
you could place or velcro a compact amp on top , might be interesting

ps
meanwhile .....
I’m gonna try my a Toob Metro in the
vertical upfiring at some point ....
which in the small/medium rooms
I play in ,may well do the trick just fine
and not need a waveguide at all
.... dunno we’ll see (or hear in fact)

cheers

[sgosnell]

Yes, the cones were plastic, somewhat parabolic. They don't need to be out of any particular material, as long as it is reasonably smooth and will reflect sound waves. I think shape is more important than material.

[Herbie]

Amazing and futuristic looking inventions these Zeniths!

After thinking positive about these real and planned 360 degree gadgets (I don’t know what is plural form of the word apparatus) I figured a normal club or concert situation and started to wonder where would such a 360 degrees apparatus be needed?

On the stage nobody wants to hear my guitar as loud as I. And if there is 3–5 players in the stage there normally is (or at least should be!) 30–300 listeners in the audience. If the volume of that 360 degree apparatus is enough for the stage it can’t be enough for the audience. The stage and aidience need different volumes, and maybe even different sounds.

In this point of view the directional cabinets are very useful in many ways in the live gig situation. You can use the directionality as a tool.

This thread has offered a lot of interesting thoughts, I have read this with joy!

[EastwoodMike]

I don’t actually have any idea what % of sound comes off the front of a speaker and how much escapes off the back side. Specifically for an open back cab. Of course it would depend on ‘how open’ the back is. If you had 100% back open though, what could that maximum be?
I agree you want the bulk of your audible energy penetrating the deepest corner of a void and not shared on stage. Hence I was wondering if there was an 80/20 or 70/30 split. Disperse the 30% amongst the stage and send the rest out to the audience?

[EastwoodMike]

Another potential tube front/SS power option up to 100W.
The Amp 100: 100W Guitar Amplifier pedal by Milkman Sound

has a 50w sibling with tremolo. 100w has adjustable reverb and boost.

Priced like a small volume boutique. Everyone starts someplace though. US built.

[pingu]

Amazing and futuristic looking inventions these Zeniths!

After thinking positive about these real and planned 360 degree gadgets (I don’t know what is plural form of the word apparatus) I figured a normal club or concert situation and started to wonder where would such a 360 degrees apparatus be needed?

On the stage nobody wants to hear my guitar as loud as I. And if there is 3–5 players in the stage there normally is (or at least should be!) 30–300 listeners in the audience. If the volume of that 360 degree apparatus is enough for the stage it can’t be enough for the audience. The stage and aidience need different volumes, and maybe even different sounds.

In this point of view the directional cabinets are very useful in many ways in the live gig situation. You can use the directionality as a tool.

This thread has offered a lot of interesting thoughts, I have read this with joy!

I have a different experience usually
in a 4 or 5 piece band , cramped ‘stage’
40-50 audience

re guitar volume ....
if the drummer has enough , the bass player wants a bit more and the pno player wants me to turn down !

or some other uneven outcome like that
(the audience seem to be happy usually
or ok at least)

this experience is why I’m thinking high dispersion might solve things ....
dunno

[pingu]

Yes, the cones were plastic, somewhat parabolic. They don't need to be out of any particular material, as long as it is reasonably smooth and will reflect sound waves. I think shape is more important than material.

you may well be right sgosnell ....
———————
or conversly .....
I’m now wondering if using
an irregular denser material as the reflector might give even better results

eg a ‘random’ glued together pile
of children’s wooden building blocks

this would ‘scatter’ the sound in all directions fairly evenly from the down-firing speaker
but would smooth-out any odd phase
anomalies in the fz response a smooth waveguide might produce



similar to ‘scattering’ type acoustic wall or ceiling panels
to help break up the standing waves etc

[pingu]

i should clarify , I’m imagining this is
for a loudspeaker system
reproducing the electric guitar
say 80hz to about 5 khz

and only if like me you want
wide disspertion

[rpjazzguitar]

I have a different experience usually
in a 4 or 5 piece band , cramped ‘stage’
40-50 audience

re guitar volume ....
if the drummer has enough , the bass player wants a bit more and the pno player wants me to turn down !

or some other uneven outcome like that
(the audience seem to be happy usually
or ok at least)

this experience is why I’m thinking high dispersion might solve things ....
dunno

I've had that problem, although with an octet. In one of our regular gigs only horns went thru the PA. If the drummer was happy, the horn players complained. Eventually, I brought a practice amp, ran a line to it from my pedal board and gave it to the drummer. He adjusted the volume.

I then positioned my main amp as best I could so that I could hear myself in the context of the group. Eventually, the complaints diminished.

Pro sound, it ain't. Sound engineers don't like multiple sources on a stage.

And, it depended on which of two pianists were on the gig. One brought a stereo setup and put one on a pole in the back of the band and the other pointing at his own head. That worked well. The other guy brought a behemoth with speakers to the front and side (at me). Blasted me out even after I complained -- nice guy, good player, but pretty insistent on being loud. I eventually found that I could put the big band book (imitation leather and thick) against the side opening of his cabinet and effectively silence that speaker. Pianist never noticed.

[nevershouldhavesoldit]

I’m now wondering if using an irregular denser material as the reflector might give even better results eg a ‘random’ glued together pile of children’s wooden building blocks…
this would ‘scatter’ the sound in all directions fairly evenly from the down-firing speaker but would smooth-out any odd phase anomalies in the fz response a smooth waveguide might produce similar to ‘scattering’ type acoustic wall or ceiling panels to help break up the standing waves etc

The surface and the material from which it’s made both matter a lot. Different reflector materials, surface finishes, shape etc will affect sound just as different speaker cones do.

Sound waves are trains of pulsatile kinetic energy. No surface or material is 100% reflective. Each dissipates at least a small amount of that energy at different frequencies into both elastic and inelastic deformation, sympathetic vibration, and other physical interactions. Some of that energy excites resonances that reinforce specific frequencies. Some of it is reflected with a phase shift because it slightly deforms the surface and its reflection is very slightly delayed. A rough surface scatters the reflections, as you suggest. A soft surface reflects less because it absorbs and dissipates energy - think carpet vs wood, curtains vs windows, but on a microscopic level. Etc etc etc - there are hundreds of studies visualizing surface behavior in sound emitting, reflecting, and damping materials.

Reflectors generally create phase anomalies. This is how Bose 901s got that “big” soundstage, and it’s why they couldn’t image worth a d@mn. It’s not as important for a guitar amp as it is for music reproduction. The rear radiation from an open back speaker enclosure is out of phase with the direct radiation. Those downfiring speakers bounce the sound off the floor, so a fair amount of it is reflected back at the speaker and ends up in a phase salad. Simple factors like an extra few mm of space between the bottom of the enclosure and the floor affect how it sounds.

[RJVB]

This seems as good a place as any to ask: how about using a hifi system (for playing at home at least)? I'm completely new to the whole amplified playing thing, but it seems to me that if you pre-amp the signal from the guitar you should get (what I understand is called) a clean signal that's as good as it can get. With the speakers you happen to have of course (Klipsch in my case, supposed to be designed with jazz in mind )

[Alter]

You would eventually destroy the speakers if you play guitar through them, especially with effects, preamps etc.. Has to do with volume and speaker response, but eventually they will give up, even if playing at low volumes..

[pingu]

The surface and the material from which it’s made both matter a lot. Different reflector materials, surface finishes, shape etc will affect sound just as different speaker cones do.

hiya never ,

do you have any knowledge or intuitions as
to what would be a good material for the
scattering pile structure at the base of my downfiring system ?
(up to about 5khz for electric guitar)

what do you think of child’s woodblocks
glued-together-randomly idea ?

I ask because
the proprietary scattering/diffusing wall/ceiling panels are often made of wood blocks in a semi random arrangement

thanks

[RJVB]

You would eventually destroy the speakers if you play guitar through them, especially with effects, preamps etc.. Has to do with volume and speaker response, but eventually they will give up, even if playing at low volumes..

That seems unlikely if your amp isn't overdimensioned for the speakers. Or else the same would happen if you play similar recorded music...
Besides, wouldn't the same happen to the speakers in an actual guitar amp?

[Gitterbug]

Despite high power ratings (from marketing dept.), home audio speakers aren't neither meant nor built to take the physical punishment of live music on stage volumes. Cab makers who don't use dedicated guitar/bass speakers install pro audio (=PA) drivers instead. I've heard a half-acoustic ensemble using small Genelec monitors to their complete satisfaction, but the volumes were quite moderate.

[marcwhy]

As with other examples above, this sort of thing and the Toob maybe should be the future, but musicians can be more old fashioned and stubborn than we'd like to think!

[BTW, I have the unpowered PA Sonuspeaker, which they don't seem to list any more, and it works great! I've also owned the bass speaker.]

[RJVB]

Despite high power ratings (from marketing dept.), home audio speakers aren't neither meant nor built to take the physical punishment of live music on stage volumes.

I think I mentioned I meant home use, no? No way I'd schlep my hifi equipment around, esp. not if the goal is to damage the hearing of audience at the far side of a football stadium.

But we're talking about jazz guitar amplification here ... how often does one use big stacks of 1000s of watts for that?